[PATCH 1/4] gpiolib: Add gpiochip_find_by_name() and gpio_find_by_chip_name()

[Grant Likely]

On Fri, 2 Mar 2012 11:06:15 -0800, Tony Lindgren <tony at atomide.com> wrote:
> * Grant Likely <grant.likely at secretlab.ca> [120302 10:16]:
> > On Fri, 2 Mar 2012 10:08:48 -0800, Tony Lindgren <tony at atomide.com> wrote:
> > > * Tony Lindgren <tony at atomide.com> [120302 08:31]:
> > > > * Grant Likely <grant.likely at secretlab.ca> [120302 01:00]:
> > > > > On Thu, 01 Mar 2012 10:55:24 -0800, Tony Lindgren <tony at atomide.com> wrote:
> > > > > > +
> > > > > > +/**
> > > > > > + * gpiochip_find_by_name() - iterator for locating a gpio_chip by name
> > > > > > + * @name: name of the gpio_chip
> > > > > > + *
> > > > > > + * Similar to bus_find_device_by_name. It returns a reference to the
> > > > > > + * first gpio_chip with matching name. It ignores NULL and empty names.
> > > > > > + * If you need to do something more complex, then use gpiochip_find.
> > > > > > + */
> > > > > > +struct gpio_chip *gpiochip_find_by_name(const char *name)
> > > > > > +{
> > > > > > +	if (!name || !strcmp(name, ""))
> > > > > > +		return NULL;
> > > > > > +
> > > > > > +	return gpiochip_find((void *)name, match_name);
> > > > > 
> > > > > Nasty cast.  Can the signature for gpiochip_find be changed to accept
> > > > > a (const void *)?
> > > > 
> > > > I think so, this too comes from the bus code.
> > > 
> > > Looks like it can't be const as of_node_to_gpiochip uses it with
> > > a struct device_node * that for of_get_named_gpio_flags comes from
> > > of_parse_phandle_with_args.
> > 
> > Really? It sees to work fine here:
> 
> Hmm right you are. I must have missed adding the const to
> of_gpiochip_is_match, that's good news :)
> 
> Want to do that as a separate patch or want me to fold it in?

I've got it as a separate commit in my gpio/next branch.

g.

> > ---
> > 
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index d773540..e633a2a 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -1152,8 +1152,9 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
> >   * non-zero, this function will return to the caller and not iterate over any
> >   * more gpio_chips.
> >   */
> > -struct gpio_chip *gpiochip_find(void *data,
> > -				int (*match)(struct gpio_chip *chip, void *data))
> > +struct gpio_chip *gpiochip_find(const void *data,
> > +				int (*match)(struct gpio_chip *chip,
> > +					     const void *data))
> >  {
> >  	struct gpio_chip *chip = NULL;
> >  	unsigned long flags;
> > diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
> > index e034b38..bba8121 100644
> > --- a/drivers/of/gpio.c
> > +++ b/drivers/of/gpio.c
> > @@ -229,7 +229,7 @@ void of_gpiochip_remove(struct gpio_chip *chip)
> >  }
> >  
> >  /* Private function for resolving node pointer to gpio_chip */
> > -static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
> > +static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
> >  {
> >  	return chip->of_node == data;
> >  }
> > diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
> > index 1ff4e22..5f52690 100644
> > --- a/include/asm-generic/gpio.h
> > +++ b/include/asm-generic/gpio.h
> > @@ -142,9 +142,9 @@ extern int __must_check gpiochip_reserve(int start, int ngpio);
> >  /* add/remove chips */
> >  extern int gpiochip_add(struct gpio_chip *chip);
> >  extern int __must_check gpiochip_remove(struct gpio_chip *chip);
> > -extern struct gpio_chip *gpiochip_find(void *data,
> > +extern struct gpio_chip *gpiochip_find(const void *data,
> >  					int (*match)(struct gpio_chip *chip,
> > -						     void *data));
> > +						     const void *data));
> >  
> >  
> >  /* Always use the library code for GPIO management calls,
> > 

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